Oestrus patterns of progesterone-treated Yankasa ewes in the hot dry and late wet seasons

Differences in oestrus patterns of 20 Yankasa ewes of 2 age groups (Adult vs Yearling) in hot dry and late wet seasons were investigated in a 2 X 2 X 10 factorial experiment. Mean oestrus cycle length was significantly (p0.05). Season significantly affected the frequency of oestrus, while age group did not. No behavioural oestrus were observed for 60 and 0% of the ewes in the hot dry and late wet seasons, whereas 25, 15 and 0% of the ewes in the hot dry and 5, 10 and 85% of the ewes in the cold dry season came on heat once, twice and thrice respectively, within a period of 40 days. The observed disruptions in the oestrus cycle of the ewes in the hot dry season confirm the heat stress effect on the reproductive behaviour of ewes